This invention relates to an apparatus for feeding cut products, such as rolled tissue product, from a log saw to a wrapper. The rolled tissue product can include bathroom tissue and paper towels.
In all present art, cut product from the log saw is randomly conveyed and accumulated on a belted or plastic chain conveyor that is typically 65 to 100 feet in length. The cut product is conveyed to the wrapper, where a set of metering belts (choke belts) coordinates and times the placement of the product as it enters the wrapper. A typical metering belt system is disclosed in U.S. Pat. No. 4,159,760.
To insure that the product is properly conveyed into the metering belts, the surface speed of the conveyor must run at a rate faster than the average speed of the metering belts. If the number of infeed lanes feeding the wrapper exceeds the width of the package format being produced, the metering belts must “converge” the product into the wrapper. During converging, product on the conveyor must accelerate and decelerate to intermittently feed the proper number of infeed lanes. The surface properties of the conveyor must generate sufficient frictional forces to accelerate product into the metering belts without leaving gaps between successive rolls. The acceleration rate is high when converging from four or more infeed conveyor lanes down to one, two, or three lanes into the wrapper.
The problem with the present art is that cut roll product exiting the saw becomes randomized before entering the wrapper. The wrapper must reestablish an organized and timed flow of product to complete the wrapping process. Conventional conveying systems require friction between the product and conveyor to properly transport the product to the next operation. Excessive friction levels damage the outer surface of the product or package, while insufficient friction levels result in gaps and improper product placement at the next operation. The friction levels are difficult to regulate because they vary with the amount of product residing on the conveyor and the surface speed of the conveyor. The infeed conveyors are usually very long, typically 65 to 100 feet in length, and require a significant amount of floor space. The conveyor length is determined by the desired friction levels and also by the amount of product accumulation needed in case of a process interruption. Product accumulation is needed because the operating speeds of the log saw, wrapper, and bundler are typically not coordinated with one another.
Another problem with the present art is that the metering belts are known to cause product damage. Metering belts are typically used to compress, hold, and regulate the position of the product as it enters the wrapper. The compression forces must be sufficient to withstand the frictional forces generated by the infeed conveyor so that the product does not slip in the belts. The force is very difficult to regulate as product firmness and/or product diameter varies.
To solve this problem, a method is needed that eliminates the randomness and accumulation of product between the log saw and wrapper. The cutting and wrapping processes must be combined and coordinated with one another, rather than having each process operate independently. The method used to transport and time the product between the log saw and wrapper should not require conveyor belts or metering belts, as both are known to cause product damage.